They also tend to be more distracted (more noise going on, more footsteps, people talking, etc.)
So the suggestion is to lower the movement speed of all groups on the world map to 0.8 (orc ambushes, adventuring parties, and all friendly patrols) and possibly reduce their vision radius.
This will make the encounters more avoidable without making them any easier when you do encounter them. In other words they'll become more like opt in encounters so if they kill you, well it's your own fault